Symbols are useful for identifying data. In one example, the data may represent persons, places, things, numbers, course, speed, directions and so forth. An important characteristic of symbols when used in a system is that users using the system know what each symbol represents and use them in the same way. In the U.S. military these symbols are standardized. For example, the U.S. Department of Defense uses Military Standard 2525 as a standard for symbols.